Why does my label appear without any color?

This issue usually arises when labels use “legacy” colors. It’s worth noting that Gmail’s web interface no longer offers the option to select these colors, although it does still retain the capability to display them within Gmail itself. However, the Gmail API does not expose these colors to any email client, such as Mimestream.

To resolve the issue, we recommend selecting a new color from Gmail’s updated color palette. You have the flexibility to make this selection either within Gmail’s web interface or directly from Mimestream by performing a control-click on a label and then selecting a new color from the menu.